1. Field of the Invention
Medical and laboratory equipment: fixed apparatus for equipment; instrument or tool for medical or laboratory use; surgical forceps. Surgery: surgical instruments; orthopedic cutting instrument; rongeur resector or nipper; gouge forceps, and instrument for removing tiny fragments of bone; forceps having jaws biased to open or closed position. Forceps having a jaw structure; forceps having a hinge or latch structure; forceps having a tubular member stripper.
2. Description of the Prior Art
FIG. 1 of the drawings illustrates a typical prior art rongeur. The rongeur is a hand held device used by a surgeon while performing surgery. The illustrated rongeur is commonly referred to as a laminectomy bone rongeur. There is also available a Kerrsion pituitary rongeur, which has a scoop-like cutting head such as the one illustrated in FIGS. 16-18 in the drawings. There are perhaps fifty different styles of rongeurs available. The different versions are a result of different cutting tips, different rongeur lengths usually being from six inches to eleven inches, and different handle grips and spring combinations. The proximal tip of the rongeur is its essence. The surgeon requires a surgical instrument that can be used to remove calcification, to trim away part of a bone, and to assist in bone fusions. The rongeur is also commonly used to take tissue samples for biopsy purposes, and to remove portions of tissue during the operation.
The typical prior art rongeur has an angled upright rear stationary handle which changes at its upper portion into an integral stationary shaft extending horizontally from the upper portion of the stationary handle. The distal end of the stationary shaft has an immovable cutting tip. There is a second upright movable handle attached near its upper end by a pin screw to the area where the stationary handle changes to the stationary shaft. The attachment functions as a fulcrum point for the movable handle. The pair of handles form an inverted V-shape in profile. There is a movable shaft which rests on top of the stationary shaft. The distal end of the movable shaft also has a cutting tip and its proximal end engages with the top of the movable handle. The pair of shafts have complementary tongue and grooves to keep them slideably locked together. The tongue and groove joint also allows the movable shaft to slide back and forth over the stationary shaft. An inverted V-shaped tension spring is placed between the two handles to keep them spread open sufficiently and also to keep the two cutting tips open at the tips of the shafts. The spring also provides resistance and gives tactile feel to the surgeon when he is squeezing or relaxing his grip on the handles while using the rongeur. By squeezing the handles together, The top end of the movable handle pushes against the proximal end of the movable shaft. As a result, the moving cutting tip on the movable shaft slides toward the stationary cutting tip on the stationary shaft. The open bite area between the two tips is positioned at the place where the surgeon wishes to remove material. Any material positioned in the bite area while the surgeon squeezes the handles together will be snipped off or punched out as a result of the movable cutting tip pressing against the stationary cutting tip.
The stationary cutting tip can have many configurations. It is typically pointed up or down and frequently has an offset angle. The perimeter of the tip extending from the shaft forms a semicircle in profile from 3 to 5 millimeters in diameter. This area inside the perimeter usually has a recessed cavity to allow for the snipped off piece of bone or tissue to lodge itself. The movable cutting tip has a bevelled edge with a flat or recessed face. The two tips form complementary faces and edges so that there will be a clean cut made by the rongeur.
A series of rongeurs having different tips and sizes are made available for the surgeon during the operation so that he or she can use them as called for. The tip style for a particular rongeur cannot be changed, nor can the typical rongeur be disassembled after use for ease in cleaning or for replacement of broken parts.
The most serious shortcoming found in the typical rongeur is in the frequency of broken tips. A broken tip renders the rongeur useless. It cannot be refurbished economically and is usually discarded. It is an important object for nearly all rongeurs to have a small cutting tip, which is commonly referred to as a small footplate. Surgeons request the small tips because they are easier to work with and they minimize the trauma caused by the surgery itself. A typical rongeur is designed to withstand 500 pounds of force or stress at the tip before breaking. When the surgeon grips and squeezes the handles towards each other, the squeezing force is multiplied by the lever action of the movable arm pushing against the proximal end of the movable shaft. The movable cutting tip is caused to press against the stationary tip in response to the surgeon's squeezing grip. The stationary tip has to be able to withstand the force of the movable tip pressing against it during the snipping and cutting process. If the force exerted by the surgeon exceeds the designed limits, the stationary tip or shaft will bend or break. The surgeon's requirement for a small footplate places limits on the structural strength and rigidity of the stationary shaft. As a result, breakage is common from over squeezing by the surgeon. Because of this shortcoming, replacement of expensive rongeurs and maintaining an inventory of different tipped rongeurs results in unnecessary expenses for hospitals, which is passed along to the patient.
The inventor realized this problem and invented the rongeur as shown and described herein to alleviate or solve the aforementioned problems regarding prior art rongeurs.